The present invention relates to isolator switches of the high voltage type, and more specifically to an improved, readily manufactured contact assembly for engaging the movable parts of such a switch.
Although isolator switches are not ordinarily intended to interrupt large currents, as they are usually placed in circuit with power transmission lines they must be able to carry large currents and to sustain very high voltages. Thus the electrical characteristics of these devices are quite critical. Good conductive properties, resistance to arcing or the formation of corona, and longevity are of the utmost importance. However the mechanical attributes of the switches are of equal importance. The switches are conventionally of very large size and weight, and are often mounted high in the air. They are usually located outdoors in remote power stations and therefore must have a high degree of mechanical strength and integrity.
The large, movable operating components have to be virtually trouble-free over a long period and thus are usually of heavy construction. Often large, heavy castings and specially-made metal parts are used in order to assure the integrity of operation and electrical characteristics which are needed, while providing the needed strength and rigidity.
If cost were no object it would not be difficult to design elaborate switch mechanisms which operated in the desired manner. Of course, the absence of cost constraints does not guarantee that a design will be mechanically straightforward and trouble free. However, in recent years the need to produce cost-effective, efficient designs has become more urgent and efforts have been made to devise switch mechanisms which are better than those previously known. Nonetheless, to date many manufacturers have produced designs which are complex and costly, and which rely upon large, specially cast or machined parts for their switch mechanisms.
It is therefore an object of the present invention to provide an improved isolator switch.
It is a further object to provide an improved switch mechanism for isolator switches.
A further object is to produce a switch mechanism which does not require large, expensive castings for the saddle portions thereof.
Yet another object is to provide an improved contact assembly in a double-end break style switch.